Gun perforator



Sept. 27, 1960 F. V. PORTER GUN PERFORATOR Original Filed Dec. 8, 1950 Eek?- flap/e557- 14 1 02752,

ATTOEA/EV Patented Sept. 27, 1960 ice 2,953,971 GUN PERFORATOR Forrest V. Porter, Monterey Park, Califi, assignor, by

mesne assignments, to Dresser Industries, Inc., Dallas, Tex., a corporation of Delaware Continuation of abandoned application Ser. No. 199,769, Dec. 8, 1950. This application Oct. 4, 1954, Ser. No.

12 Claims. (Cl. 89-1) This invention relates to gun perforators and particularly to well perforators of the type adapted to be lowered into a well borehole and in which a bullet or projectile is fired from the gun to pierce the surrounding well casing and formation to open the same for the flow of fluid into the well. More specifically, this invention relates to the construction, arrangement, and mounting of the in such manner as to provide initial restraint thereof during initiation of combustion of the propellent charge, the

sealing of the firing chamber against external fluids, and i the precluding of premature firing, particularly in response to external pressures, as Well as the relation between bullet and propellent charge for obtaining maximum ballistic efficiency for the gun. It is also desirable to provide a combined charge and bullet loading unit assembly which may be preassembled under factory supervision and control, and which may be safely transported and installed in the perforator gun with a minimum of time and effort and with a resultant maximum of uniformity in characteristics of operation. I

These and like problems of perforating gun construction and operation have long been recognized. Noteworthy steps in the solution thereof are exemplified in the prior patents of others skilled in a manner designed solely to improve one particular aspect of the total combination of factors, and in so doing, collateral weaknesses have been ignored. In the present construction, all of the above-mentioned problems and others related thereto have been considered as a whole to the end that improvements in the individual functions combine, without sacrifice one to another, to provide a new and improved combination and interrelation of parts. In such combination, improved efiiciency and effectiveness are achieved in a novel,

simple manner readily designed to meet the demands of economic manufacture.

It is, therefore, an object of the present invention, to provide a novel and improved perforating gun having a plurality of combining and cooperating features of advantageous character, the sum of which represents a total advance in the art along several heretofore separately vide new and improved means for mounting a perforating bullet in a perforating gun in such manner as to provide in effect a barrel of extended length for the bullet, and to secure the same with a new and improved manner of bullet restraint so as to secure new and improved ballistic efficiency.

Another object of the invention is to provide a bullet and propellent charge combination such that premature firing of the charge will not result from an inadvertent subjection thereof to excessive fluid or mechanical pressure.

Another object is to provide a novel and improved charge to igniter relation and to provide a variable propellent charge to air or gas volume ratio which may be selected, adjusted, and maintained, such being one means by which the ultimate firing force and bullet penetration may be improved.

Another object of the invention is to provide a novel and improved sealing means for the firing chamber of a gun perforator, an improved feature of such sealing means being its responsiveness to pressure within the powder chamber, whereby the greater the propellent gas pressure applied, the greater the sealing effect.

It is another object of the invention to provide a gun perforator construction in which expendable parts are used where the erosion and deteriorating effects of the propellent gases are greatest, thereby in effect maintaining the gun unit in substantially new condition.

It is another object to provide a gun perforator structure in which provision is made for replacing the igniters when reloading the gun, without the necessity of disturbing the breech assembly and associated electrical connections and wiring leading to the igniters.

These and other objects and features of the present invention will be apparent from a consideration of the following specification taken in conjunction with the accompanying drawings, in which:

Figure 1 is a view in elevation of a typical well perforating gun embodying the features of the present invention, and

Figure 2 is a transverse section taken on the line 22 of Figure l. i

In the drawings, the numeral 10 indicates the gun assembly generally, and the numeral 12, the gun body. The gun comprises a steel cylindrical assembly which is adapted to be lowered into a well bore hole by a conductor cable 11, containing an insulated conductor or conductors, through which the firing of the units may be controlled. As indicated in Figure 1, between the conductor cable 11, and the body 12 of the gun, there are provided a cable socket 13 and various interconnecting subs, one of which, as shown at 14, contains suitable fire control means, as indicated in dotted lines at 15, with respect'to which the present invention is not specifically concerned, but which will be referred to in more detail hereinafter.

Referring more particularly to Figure 2, the gun body, indicated by the numeral 12, comprises a generally elongated substantially solid steel cylinder of sufficient strength and solidity to withstand the explosive forces of the firing of the gun charges. Laterally directed gun units are mounted in the cylindrical gun body at longitudinally spaced intervals and preferably in a spiral arrangement, as shown in Figure 1. Each unit comprises an internally threaded, laterally directed barrel opening 16, which receives the threaded barrel member 17. In the form of a barrel member here illustrated, the outer end portion 18 is reduced in external diameter and given a hexagonal shape in order to receive a suitable tool or wrench for its installation and removal. Preferably, the lateral depth of the barrel opening 16 and the length of the barrel member 17 are such that the barrel memberis wholly received within the openthe charge chamber.

ing, as withthe surface of the gun body, whea fully seated and tightened therein, so as not to present any laterally projecting parts when the gunis fully assembled in the manner shownin Figures} and 2. ,Theinner end of the barrel rnernber 17 is ft rrrned w i tlra smooth thread-free end '19, of slightly red-uced external] diar rieter, adapted to be received concentrically lwithin an inner thread-free, counterbored end' recess 29, 111? the barrel opening 16, thereby forming there between a short annular end recess. An ring 2 1 is seated within the beforernentioned annular end recess, between the sur faces 19 and 20, order ,to seal the bar rel'rnemberwithin the barrel opening and to preclude leaking of any well fluid inwardly from between the threadedportion: of

' the gun barrel O-Pfll g 16, and the 'ext:erna l ,Slillifge of the barrel mernber 1-7 Thebarrel member-1 7 is formed with a concentric barrel b,ore, 22 9 f ge eral-1y uniform inside diameter, but having,- at the outeror muzzle end thereof, a short portionat slightly enlarged diameter, forming ashallow recess 23, having an' annular shoulder 24; Seated within-the recesslfaf and making sealing engagement against the shoulderuz l, there isprovided a sealing dise- 25 for preventing admission of well fluid sealed in any suitable manner well known in the art, and maybe formed of any-suitable material, such as brassor "steel, In operation, when thepropellent charge is detonated and-the bullet fired; the seal 25 is ejected from the recess 2 3, either as a 'unit or as fragments,

and forms substantially no obstacle tether discharge of the bullet;

material 45, f orrnedwith an openinglorflpasisiag' 46- extend n sen ra 1y-: ethr0 sh t m dp-tqe ds ch ise" bqdy 145: is "surrounded ind" 9 I1'-? 'fit, the outer cylindrical V 33 of th'e diaphragrn 30. 1 The-firing cha'rge comprises a bore "or recess142:,v of jstill: smaller"diametenis'forniedin Y 1 i ;the inner end wall 43 "of. the'firingchargefchamber 40 g l "to receive an igniter'head tofnthe firing. means fur;

ther referred .to "hereinafter during the final loading operation in the 'field. Theinternal diameter of 7 the" bore 41, forming the s ide ,v ya1ls"of the firing' charge: H chamber 40, is such as to snuglyreceivmby a handpress fth an u r secompressedlmolded; or I otherwise'consolidatedbrflpelletil ize'd," tubular ,shapd offeombustible propelleintfll v posedof suitable material, preferably sn'onmetallic, such as, for "i example, a paper or cloth ,base, phenolic-impregnated hina container sleeve or shell 47, which may becom tubing. 7 The propellentcharge body makes a loose fit i 7 surface of the charge body and the inside" surface [of j l V the sleeve. Thecontainer sleeve 47- preferably extends, =5 1 'WithinEthecQntainer sleeve -4'7 preferably with a-sub- Y stantialiannular clearance space between 'the outside a short distance forw'ard lofthe forward end of the,

' tpropellent charge body and fits lwithin the flange34 of into the barrel bore. {The disc 2 5may be seated and The 'well casing or formation piercing projectile or bullet of-the present gun unit is indicatedrat 26, and preferably comprises a forward piercing nose portion 27 of substantially conical or ogival form, and a body or rearward shank portion =28, preferably of uniform diameter, extending from the nose portion '27 to the ,t-ransverse rear end or butt 29. -The bullet;26 is usually 'made {of hardened steel or steel jacketed in a manner well known in the industry to provide adequate casing shape here shown is now believedQ-preferiable in the present'eornbination, it will be understood that the'inyen- ,tion is not limited -to-this specific design (if-bullet,

Various types 'ofjn ose formations and shapesirnay' be resorted to as desired,'in aecordance with the dictates of the-particular perforation 'Qperationto be performed. The" bullet 26 is mounted through a central opening formed iin a sealing plate or diaphragm 30, and also through a frusto-conical restraining annulus 3 1, both of which engage the cylindrical midsection of the bullet approximately midwaybet-ween the forwarden'd of the nose portion 27 and the butt -29. -While the plate-30 and=the annulus -31 are here shown asseparate parts, they may be integral. The openings thro ug'h both plate 30 and annulus 31 are preferably such as "to form a tight press-fit :upon the bullet 26, t-he annulus-Stand plate 30 being either in juxtaposition or of integral construe:

, 1 or formation piercing ability. Whileabullet of the V cylindrical portion 28 ofjthe bullet 26 which is :here

gluing or cementing itsedges to the endinargin of the l container sleet/e747. The-central opening, extending through the charge 45, has an internal diameter slightly greater than the external diameter'of the cylindrical body I i tportion 2 8 of the bullet 2L6; 'whenthelcharge andbullet i are assembled, the bullet extends within the central i opening 4 6 for approximately onehalf the length of the shown as approximately one-third the length of the charge 'In this arrangement, it will also-be seenthat, as "assembled,the rearwardend of the annulus 31 tionto form a holding unit, from which thebulletfis dislodged only upon firing ofthe propellent charge' and the burlding up of a suflicient initial pressure-within 34 of which is cylindrical-and coaxial with the disc portlon and centrally contained bullet, while the inner surface 35 is slightly tapered in a rearwardly diverging direction, forming thereby a-frusto-conical surface disposed at opposite angularity to the rearwardly converging frusto conical outer surface 36 of the annulus 31.

j A cylindrical firing charge eharnberj shown ,at 40 formed by a bore 41 of inside diameter reduced relative to that of threaded barrel 1-6 but uniform throughout its Theperiphery of the diaphragm i if 30 has formed thereon and integral-therewitha rear-t :wardly directed annular 'flange'or lip 33, the outer face length, and xtendingconcentrical'ly inward from the innermost :end" of the barrel opening 16. concentric varying conditions and requirements, the relationshipsx andquantityof'a given c harge, so that theballistic char acteristicsxand penetrating {ability of vthe: unit may -be varied by change in size of the'charge andtpositio-n of p a It is also important to notethat'in the presentasseniis spaced from the forward end of the charge 45. Since the cylindrical propellent charge assembly terminates at 1 'eachend in plane, transverse surfaces," except for the chamfered, forward Iedge of the 'passage46, it will be notedrthat antannular air or gas space 51 is 'formed between the charge and the plate 30 surrounding the annulus fil. In thepre s ent instance, the space 51 is approximately equal in depthtojthe thickness of the annulus 31. The character, size, density, and shape of I a the, propellent'char'ge may, of course, be'varied as suit here suggested being only byway of'exarnple as having been found effective and-eificient in certain perforating V practices. It is importantto note that the present assema V bly provides the combustion clearance'space- 51, and that such space is variable, depending upon thedensity the bulletnloading unit. 'LThus, .by change-of density of i 2 given quantity'of,charge, the ballistic. characteristics 0f the unit may be. altered sornewhat"without'change in t the router dimension of the charge ,and fbullet assembly? and-without alteration or adjustment offthe size and shape of the gun'parts. 1 i i l l 5 bly, the bullet retained within thefiringchamber with on; direct contact with the charge; By yirtueof the fae thatthe bullet 'diameterfis slightly less than t j the m imu inside dia ter ptth )P 't 'l g,4 e1 sl ,k the propellant vC arg .bpd l fiiithefl bul etz i is free y 1 same rearwardly, as by a premature rupture of the sealing disc 25, and the admission of well fluid pressure to the nose of the bullet, rearward movement of the bullet will not act to compress the charge and, by such compression and the resultant friction and heat thereof, prematurely explode the charge. An important safety factor is, in this manner, incorporated in thepresent design.

A further important feature of the present invention is the fact that the bullet 26, plate 30, annulus 31, charge 45, and container sleeve 47 may be readily assembled at the factory and under factory supervision and control, as a sealed loading unit protected from external moisture or other contamination. Such units may then be transported to the field or other loading locations and conveniently loaded into the gun with a minimum of time, effort and of danger, and with maxi mum insurance of uniformity of operation. The individual charge and bullet loading unit assembly is formed by press fitting the bullet 26 through the plate 30 and annulus 31 respectively. Preferably, such fitting may be accomplished as a single operation. The charge, having been suitably formed and placed within the container sleeve 47, is then sealed over at the rearward end by the paper wafer 49, and the forward free end of the container sleeve 47 is then fitted within the frusto-conical walls 35 of the flange 33 and secured there by gluing, cementing, or the like, at 48, as beforementioned. The loading unit, thus formed, may be transported with relative safety, it being noted that the igniter is not included in this loading unit but is applied to the unit as an incident to the' final loading of the gun. venience, and uniformity of performance are thus insured.

As will be hereinafter referred to, the securing of the forward end of the container sleeve 47 within the lip 33, provides against dislodgment of the container 47 from the plate 30 under the high pressure resulting from combustion of the propellent charge, and will not only force the container sleeve end more tightly outward against the inner surface of the flange 33, but will also expand the flange 33 more tightly outward against the inner wall 41 of the bore 40, and thereby effectively prevent leakage of the propellent charge gases outwardly to the space between the rearward end face of the barrel member 17, and the adjacent forwardly directed face of the annular end surface surrounding the charge chamber bore opening, which might otherwise result in dislodgment of the gun barrel member 17 from the gun upon firing of the charge.

In the present embodiment of the invention, firing of the charge 45 is provided for by an igniter 44, which is preferably a cup-like head member, containing a combustible powder and an electrical resistance element therein (not shown). One example of an igniter of this type, well suited to the present purposes, is that disclosed in the patent of Robert A. Phillips, Patent No. 2,649,736, to which reference may be had for further details of its construction and operation. The head of the igniter 44 is seated by the operator during final preparation in the field for firing, within the recess 42, and extends forwardly therefrom into the firing charge chamber 40. When the loading unit is inserted into the firing chamber, the head of the igniter 44 ruptures the paper membrane or cover 49, and extends into the end portion of the passage 46 of the propellent charge 45.

Prior to installation of the loading unit, including the Safety, conpropellent charge body 45, in the charge chamber 40, V

metrally opposite the barrel opening 16 and rounded at e E3 its rearward end. An annular seal receiving recess 56 is formed at the rearward edge of the recess or cavity 55 at the surface of the gun barrel opposite the muzzle. Within the passage 53, the igniter stem 52 is surrounded by an insulating sleeve 57 and a similar insulating spacer 58 is provided in the counterbored portion 54; the threaded extremity 60 of the stem 52 receives a conductor-connecting Washer 61, and a securing nut 62. The washer 61 and nut 62 are preferably embedded together within a sealing and retaining body 63 composed of rubber or the like resilient insulating material, tightly fitted, preferably under pressure, within the recess 55. For sealing the recess 55, and retaining the member 63 therein, a seal disc 64 is tightly pressed or driven into the shallow annular recess 56 surrounding the outer or rearward edge of the recess 55.

By this construction, it will be noted that the retaining member 63, with its nut 62 and washer 61, are held relatively stationary within the recess 55, in axial alignment with the passage 53, while the igniting head and its threaded conductor stem 52 may be inserted through and removed from the muzzle end opening of the gun unit as desired, without disturbing the sealing body 63, the electrical wiring and connections and the seal disc 64. Thus, after each firing of the gun, the igniters may be replaced prior to reloading, through the barrel opening and change chamber with a minimum of time and difiiculty.

Energization of the igniter 44 is provided for by an insulated conductor 65 which is connected to the igniter stem 52 through washer 61, and extends from the recess 55 through a lateral duct 66 to a longitudinally extending conductor passage 67, formed in the side of the gun barrel and thence up through the passage 67 to the ignition control device 15, which may be contained in the top of the gun assembly 10, as hereinbefore mentioned. In case it is desired to fire each gun unit in the gun body separately, separate conductors are provided for each gun unit, which conductors makeconnection with and extend from each of the igniters of each gun unit, in the manner shown in Figure 2, and extend through their respective lateral passages into the longitudinal passages 67 and 67, as shown in part at 68 and 69, and thence up to the beforementioned firing controller 15. Two diarnetrally opposite longitudinal passages 67 and 67 are preferably provided in the gun body, to which the several latenal ducts of the type shown at 66 may conveniently make connection from the gun units which are directed at different angles along the length of the gun body. It will be noted that the arrangement of recesses 55, ducts 66, and intercommunicating passages 67 and 67', pro vides internal, fluid tight passages for the controlling conductors, and, therefore, the possibility of accident and damage thereto is minimized, so that they will not be subjected to pressures of or contact with well fluid. By this arrangement, repeated firings and reloadings of the gun may be accomplished without disturbing the conductors or opening the recess 55 and without removal of the insulating and positioning member 63, or seal disc 64, all of which may be semipermanently installed and sealed upon the original assembly of the gun body.

In the assembly of the gun proper prior. to loading, conducting wires, as shown at 65, 68, and 69, are located within the passages 67 and 67 and led through the lateral ducts 66 as desired, the grooves having been closed and permanently sealed by welding the cover plates 70 and 70 in place. The individual conductors 65, 68, and 69, are then attached to their respective conductor washers, as shown at 61, in Figure 2, which are embedded with the nuts 62 in the insulating and positioning member 63. After such connection, the members 63 are inserted in the recesses 55, preferably with a tight fit and with the threaded holes of the nut axially arranged with respect to the axis of the passage 53 and the firing chamber bore 41, so as to threadedly receive the stems of the igniters. The-assembled and wired nuts 62, washers V 61, and members 63, are

the ?seal discs '64 .and'ma-ySthus. be retained in suehtpo'si The next step in ipreparingtthe: gun foroper'ation prior 7 to rloading is sinstallingitlre igniters, whichinay be done 7 at-any timezafter' thenssembly of the wiring andthe nuts 7 62, as beforedes'cribe d. Installation of lthe figniters is readily accomplished by insertingnthe stem's. thereof through the passages 53; 54', iand threading :fliestem' into a the nuts, :as sh'OWn at "'62, by'fwhieh the heads are securely fastened .within the recesses? :of' the {firing chambers; As "an incident to thus installing the ig'nitors,

as beforedescribed Independently o'fthe nu'lus '31, are rererabi assembly within the "container sleeve 47 and sealediby the 'sealing'rnember 48 to form v a =gunzloading unit. Preferably, although not necessarily, thefchaijge 45 is "formedand compressed within the sleeve 47 and the paper membrane or seal'49is applied as beforernentione d, to seal one end thereof. In a jsep'ara te Operation; the bullet 26 is press fitted'throngh the central apertures of 'the disphragrn 30 "and annulus 31, which,

' as hereinbefore ug-gested, may be formedtogether as a single integral unit if desired. In securing the bullet V p in the annulus 31 and the plate 30 it .will be understood that eithrgor both, and preferably the annulus, grips the bullet with sufficient force to hold the same against the initial pressure following ignition of the propellant] charge tdallow the pressure. to build up behind the bullet to some extent before the bullet is expelled from the barrel, in order to insure a maximum bullet velocity. :Mounting' of the plate and annulusdirectly against the rear 'end of the barrel member with the rear end portion of the bullet extending into the charge chamber, provides an effective increasein the barfrel length. r

'With the {bullet 26 thus assembled with plate soran'd re'straining annulus 31, and with th'e'charge mounted within its container sleeve 47, the forward end 'of the a container sleeve is *then placed within the fian ge 33 of the plate 30 and is 'sealedjthereto at 35, either b'ya press fit or with a suitable adhesive or cemeng or thelike sealing nie'ans la s bforede'scribed. Thus, the plate 30 and bullet 2.6 cooperate with the container. '47 and its fabrication and assembly of the gun .proper,'='the 'ch'ar'ge 45, "bullet'26', plate 30, and anficient forceibeing applied to rupture the sealingwafer 1 49,.tl1uspern1itting'the opening 462of the charge 451m be'forced over the head of the "igniter 44Lf1As herein before noted, the internal diameter .of" the bore" '41 1of the charge chamber 40am that of the external 'face '34,

of the flange 33.1 of thediapliragm SQ'is S'ucIr' as to pr0-' vide a snugfit therebetween. As indicated, Ythejtubular container 47' is of uniform'external diameter,and since a it fits Within the flangelof the diaphragm 30', rthe remainthey areeach electrically connected with their individual conductors, which "extend to the firing control apparatus, 7

' r of more tightly against the inner surfacefofthe flange 33 and will thereby act to-l'e xpand the fiange more against the inrier surfa'c'e ofithe fir-in'g 'chaniberbore' to 1 ing outer wall "of the tubularrcontainei' 47 isfl'oosely contained'within thefcharge chamber 40;:and is thiisl'free to. i expand outwardly "under the force of the'pressure of the propellent charge gasespponifiring oftthegchargep However, such outward expansion of the shell container: 47 act to force the contained marginal portionthere automatically incr'easethe efiectivenessof the seal there betweencand around theperiphery ofjthe diaphra gmljfl to prevent leakage of gases from, thecharge chamberflto' V the inner annular end portion the barrel member- 17, f L a which surrounds the charge chamber.

c While the assembly of parts is' preferably made '1 mariner herein set forth, and in the sequence indicated, j I

it will be understood that the invention, is'not restricted j. to such manner of assembly; Forjexamplejthe complete i j. gun, fully loaded andtready for firing, may beprepared 9 in: the factory. While it is a feature of the inyen'tion to provide independent and transportableloadin'g units of; i the type hereinbefore described, the inv'ention'is not "so limited, but obviously includes the assembly of the sep; 'ara'te components, 'either in the factory or inth'e field if 5 desired. V a I 5 V H After complete assem ly, and with the gun lowered intothe wellbore or casing, the individualagununits may;

be fired either simultaneously or selectively ingany'dd i c sired sequencegin any suitablemanner'we'll knownin'the" end 1 seal 49 to form a complete bullet and charge load ing unit package, fully sealedjand -protected;f rorn-conf tamination and the :ranerrts, readily transported with relative"safty, ;since the more easily exploded igjniting element is notincluded in the unit thu'sfornied. c In thu's forniing the loading unit, it will benoted that amount-1e or density of "the 'pro pe'lle'nt charge rela-j tive to the airspace proyided in the loading unit and "in the surroundi g enamser ofthe; gu'n unit, may be predetermined and controlled, as well as the restraining force between thebnllet 26and the platefiiljand annulus 31. one of the reasons for co'nt'rolbf-these' relations between the "charge and clearance spaces ar'ound thecharge is to allow for expansion of 'the charge body due to temperature rise upon lowering of the; gun p'e'rlfora tor'into" adee'p Well bore hole where temperatures are high, Alll o fsuch'fact'ors ina-y be determined and controlled in the manufacture and assembly of 'the loading unit. In this manner, unifohriity in operation ofthe gun perforator in the field is insured; Numerous variationsjin theljall stlccharacteristics of the loa'ding units may thus be built into them in the factory, and the units may'thenb'e markfed so as to permit selection of 'the'de- V sulated conductor contained in cable llfmay be located 0 t, c

' the barrel. Suchcoutwarcl movement of the bullet 26 is in dotted lines at 15. Upon ignition "of the propellent from the gun body, and suitableytoolsfmay beiapplied gun-perforating art. Forexample, the gun units may be i fired electrically by employing ani'electrically controlled selector switch of atype such as that disclosed in, the patent to-Johnso'n No; 2 ,048;4 5l. In using a selector 7 switch of this type, the separate conductors, shown at a in Figure 11 of the beforementiohe d "patenta'nd leading" 3 f Y f o the several switchcontactporntsrnerein, xfavotild correspond to or be connected to the;conductoi s shown at 65, 68, and 69', shown in FigurefZof the present ap- 5 plicatio'n, leading to each of thefusible resistance wires 9 a incoiporatedli'n eachof' the ign-ition units 44. "Other fir r" f ing control means well known in the art'rnay obviously be used in the same or similar manner. 'Asi b eforeme tioned, this firing control apparatus connected-to the i in the perforator gun assemblyltl, in the position showncharge '45 pressure will? rapidly "build up in the charge" chamber, 'tendingto propelthebullet outwardly through initially restrained with aprede'termined ho'lding force. r applied by the gripping action of'diaphragmclfll and an? nulus 31, as beforementioned, untilfthe' accumulation of 7 force behind the bullet desired for the required ballistic 1 efiiciency and effectiveness is reached', whereupon thehul- 5 -t V l let.will,be forced on through the diaphragm and annulus and" will be discharged from" the gun bore with the alesired muzzle velocity for penetration of the well casing or formation." After firing, the gun mayhefwithdrawn fro'mjthe -b rehole,; the barrelmenibelr 17.;unscrewed '9 remove, by unscrewing, the empty igniter 44, after which a new igniter may be applied in the same manner and a new loading unit, including charge and bullet, inserted, and the barrel member 17, including the sealing member 25, again screwed into place. The gun is then ready for further perforating operations.

The portion of the gun unit which is subjected to the most erosion and other deterioration by the propellent gases is the rearward end of the bore 22 of the gun barrel adjacent the charge chamber. In the present invention, the diaphragm 30 and annular ring 31 form in effeet a rearward extension of the barrel bore 22. These parts, especially the ring member 31, therefore are subjected to most of the erosive action of the propellent gases and thereby serve to shield and protect the adjacent and rearward portions ofthe barrel bore 22 from these damaging effects. Each time the gun is reloaded, these parts are replaced by new ones, as hereinbefore described, and thus this vital portion of the gun assembly is maintained in good condition.

It is to be understood that the foregoing is illustrative only, of a preferred embodiment and use of the invention; and that the invention is not limited thereby, but may include various modifications and changes made by those skilled in the art, without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. In a perforating gun for wells having a body formed with an outer barrel opening, a bore of reduced diameter extending coaxially inward from the inner end of said outer barrel opening and constituting a firing charge chamber, a cylindrical recess of still further reduced diameter extending axially inward from the inner end of said firing charge chamber for receiving the head of an igniter, and a barrel threaded into said barrel opening, said barrel having a coaxial bullet bore, the combination of: a bullet having its forwardly projecting portion fitted into said bullet bore; an igniter head mounted in said recess and extending therefrom into said firing charge chamber; a consolidated tubular-shaped propellant charge body having a passage extending concentrically therethrough from end to end thereofand positioned coaxially within said firing charge chamber with the rearward portion of said passage encircling the inwardly extending portion of said igniter head; a transverse diaphragm at the junction of said outer barrel opening and said charge chamber bore to seal the latter, said diaphragm having a peripheral rearwardy directed flange, the external diameter of which is such as to be received within said charge chamber with a light press fit, said flange having an internal surface of rearwardly diverging frusto-conical form; a cylindrical shell surrounding said charge body and fitted at its forward end within said inner frusto-conical surface of said flange, said shell being of less external diameter than said internal diameter of said firing charge chamber bore forming an annular clearance space therebetween, with said bullet being mounted concentrically through said diaphragm and extending therefrom into said firing charge chamber; and a restraining annulus mounted on said bullet intermediate the ends thereof and positioned on the rearward side of said diaphragm and adjacent thereto, said annulus having an external frusto-conical surface the inclination of which is opposite to that of the frusto-conical surface of said flange.

2. In a perforating gun for wells having a body formed with an outer barrel opening, a bore of reduced diameter extending coaxially inward from the inner end of said outer barrel opening and constituting a firing charge chamber, a cylindrical recess of still further reduced diameter extending axially inward from the inner end of said firing charge chamber for receiving the head of an igniter, and a barrel threaded into said barrel opening and having a coaxial bullet bore, the combination of: a bullet having its forwardly projecting portion fitted into said bullet bore; an igniter head mounted in said recess and extending therefrom into said firing charge chamber; a consolidated tubular-shaped propellent charge body having a passage extending concentrically therethrough from end to end thereof and positioned coaxially within said firing charge chamber with the rearward portion of said passage encircling the inwardly extending portion of said igniter head; a transverse diaphragm at the junction of said outer barrel opening and said charge chamber bore to seal the latter, said diaphragm having a peripheral rearwardly directed flange the external diameter of which is such as to be received within said charge chamber with a light press fit, and said diaphragm being formed with a central opening; a cylindrical shell concentrically surrounding said charge body and making coupling engagement at its forward end within the inner surface of said flange, said shell being of less external diameter than the internal diameter of said firing charge chamber bore forming an annular clearance space therebetween, with said bullet being mounted concentrically in and extending through said central opening formed in said diaphragm, the rearward portion of said bullet extending into said firing charge chamber; and a restraining annulus encircling and gripping said bullet intermediate the ends thereof and positioned adjacent the rearward side of said diaphragm.

3. In a perforating gun for wells having a body formed with an outer barrel opening, a bore of reduced diameter extending coaxially inward from the inner end of said outer barrel opening and constituting a firing charge chamber, a cylindrical recess of still further reduced diameter extending axially inward from the inner end of said firing charge chamber for receiving the head of an igniter, and a barrel mounted in said barrel opening and having a coaxial bullet bore, the combination of: a bullet having its forwardly projecting portion fitted into said bullet bore; an igniter head mounted in said recess and extending therefrom into said firing charge chamber; a consolidated tubular-shaped propellent charge body having a passage extending concentrically therethrough from end to end thereof and positioned coaxially within said firing charge chamber with the rearward portion of said passage encircling the inwardly extending portion of said igniter head; a transverse diaphragm means at the juncture of said outer barrel opening and said firing charge chamber to seal the latter, said diaphragm means having a peripheral rearwardly directed flange, the external diameter of which is such as to be received snugly within said charge chamber bore, said diaphragm means also being formed with a central opening; and a cylindrical shell concentrically surrounding said charge body and making coupling engagement at its forward end within the inner surface of said flange, said shell being of less external diameter than the internal diameter of the said firing charge chamber, with said bullet fitting with a hard press fit concentrically through said central opening formed in said diaphragm means and having the rear end portion thereof extending coaxially therefrom into said firing charge chamber and into the forward portion of said passage of said charge body.

4. In a perforating gun for wells having a body formed with an outer bullet bore, an inner bore of increased diameter relative to that of said bullet bore extending coaxially inward from the inner end of said bullet bore and constituting a firing charge chamber, the combination of: a bullet; a tubular-shaped pro-pellent charge positioned coaxially within said firing charge chamber, said charge having a passage extending axially therethrough from end to end thereof; transverse diaphragm means located at the juncture of said bullet bore and said firing charge chamber bore, said diaphragm means being formed with a central opening, said bullet being supported at an intermediate relatively short section thereof by means of said central opening, with said bullet being positioned with its rear end portion exposed to and extending from lent ehar'gein said passage.

said diaphragm'means coaxial l y into said firing eharge for a substantial portion of the length'of said:

birllet, s'aid bullet making a press 'fit in said central open- 7 ing snfliciently tight to delay initial movement' r said bullet therefrom into said bullet bore'following ignition of said charge; and igniter means in said fi'ring charge chamber and positioned incommunication with said we 'sage through said propellent charge body, said -passage 7 being unobstructed intermediate said ignite'r means and the rear end portion of said bullet therein.

; s'titutin'g a firing Charge chamber, the combination of: 5a

bullet; at ibular-shaped propellent charge body posibody having a passage-extending axially'therethrough from'e'nd to end thereof; a 't-rans'verse diaphragm located at the juncture'of said bullet bore and said firing charge chamber' bore, saiddiaphragm being formed with a cen-c tral opening, said bullet being supported at an interme- 7 central opening, with saidbu llet being positioned with its rear endportion exposed to and extending 'frornfsaid diaphragm coaxially into said firing'charge chamber for thereof and-positioned adjacent to and on the rearward I tioned'cciaxiallyjwithin said firing cha g mb a i a i a said bullet, said bu'll et makinga press fit infs aid central, 7 1 opening sutficientlytightfito delaywinitial movement oi "and: constituting a .firing ficlrarge chamber a barrel p thIeaded -intosaid bar rel opening and having a eoaxials bulletfbore thereth ron'gh, 1 the combination of: a bullet; iaf' l "tubular-shaped;prdpellentcharge positioned coaxiallyi Withinfsaid firing charge chambe [said charge having a I 1 passage extending; axially{therethroligh fromjend to end i thereofwandjhavingfan externalg nieter less than the internal diameter of saidifiringcchar'ge chamber; transverseldiaphragm means located at -the junction 'o f said onte rbar'rel opening,and firin g'.char'ge chamber borer ad-g 'jacen't therear end (if said"barrel, said diaphragm means being formed? hf ntrarope in with said bullet I being supported at. an v ntern!edia'te relatively shortsee L tion thereof through saidcentral openingfand saidbullet being positioned with its rearend exposed to and extend ing from said 'di'aphragm nieans coaxiallyfinto said charge chamber'for 'asitbstaiitial portion of the length of.

said bullet frorn said centralfoperiing irito said'bulletbore following ignition or said charge Land combufstible'i'gniter H v meansinsaidfiringfchargeeharnber andpo sitioried withinizy diate relatively short section ther'eofgby means of? said i asubstanti'al portion of; the length ofsaid bullet; are 7 straining annularinember separate *from said di'atihr'agmencircling and gripping said bullet" intermediate the ends side of said diaphragm, said bullet'rnaking a press fit in said annular member sufficiently tight to delay initial movement of said bullet therefrom intosaidbillletjbore following ignition of said charge; and igniter means in said firing charge chamber and positioned in communica tion with said passage through said propellent charge.

bodyfsaid passage being unobstructed intermediate said igriitermeansand the'said rear end portion ofisaid bullet therein whereby said 'igniter means is effective to ignite initially the inner'po'rtion of said propellentchargeinbaid passage. I a r 6.111 a perforating for wheels having a body formed with an outer barrel opening, an inner bore of barrel threaded into said barrel opening and "having a I coaxial "bullet bore 'therethrough, the combinationbf: a

bullet; "a tubular shaped propellent I charge body positioned coaxially within saidj firing charge chamber, said gpropellent charge body'having a passage" extending axially therethrough from .end to end thereof; transverse diaphragm meanslocated at the juncture of said outer barrel "opening and'firing charge'charn-ber bore adjacentthe rear end of said barrel, said diaphragm means being formed 3 with opening, withsaidfbtillet beings tipported at an intermediate relatively shortfsection thereof through i said opening and said bulletbe'ingpositioned with its rear end exposed to'and extendin g 'fromeaidfdiaphfagm means coaxially into said firing charge-chamber "for a's'ubstan tial portion of the lengthof said bullet, saidbullet making acp res's fit in said opening'sufiicieiitlytight -to'delayinitia1 movement of said bullet frorn'said opening into said bullet bore following ignition of said charge; and combustible igniter means in said firing'charge chamber and mediate said igniter means and the said rear end portion of said .bullet the-rein whereby said igniter niea'ri's'is ef-v fectivec to ignit initially the inner portion of saldprbpland locatedat an intermediate portion said passage reduced jtdiameterfielative to 111g ex en i a ll fll nw its positioned within saidpassage 'throughisaid propellent c charge body, said passage being unobstructed intere 7; In aprfo'rating gun for wells havingf a body formed withan but'erba'rrel opening, an innerboreof redriced bullet being positioned with its rearfend-exposedto and V 7 extending frornsaid diaphragm means "coaxially into s aida firing charge chamber forlafsub'stantial pdttiondfit'he 7' said passagesthr ough 'saidi fOplleifit charge, said ipas'sa'ge-s 1 being unobstructedintermediate said igniter means 'and the 's'aid'rearendportion 'orsaia bullet therein whereby said igniter rneansisfefiective 'tO ig'niteinitiaHythe inner: portion'of saidpropellent charge in said passage. 7 P V -8. In a perforating gun; :f or,wlls haviiig a body formed withan "outer barrel opening an inner bore of reducedfdi'arneter. relative to that offs'aid "barter opening extending 'coaxially inward from the inner end of said barrelopeningandjconstitutihg' ayfii'ing charge chamber} j i a'barre'l threaded into said' barrel opening and having'a coaxialbullet ibore thereth rough, :the combination of: a

bullet; a tubul ar shaped propell e'ntcharge'positioned' co axially within jsaid ffirin'g charge chamber, said charge.

having a pasage extending-axiallytheretlirough from end to end thereof and 'having' an external -diaineter less than the internal diameter of saidfiririg charge--ehamber transverse diaphrag'r n meaiis Iocatedat the junction 6f: said outer'bar'rel bperiing j and firingcharge chamber borer adjacent the rear end QfsaidbarreL s aid diaphragm means' being formed "with a fcentral opening, "withfisaidfbjullet beingsupportedat an intermediate relatively short' see tion of said bullet through said central epejnin land' said length of said bullet; -bul l e't rriakin'g' a press fit in said a central opening sufficiently "tfightfto delayinitial 'iriove- 1 mentof said bii ll'et' frorn aidjce ntral opening intofsaid bullet bore y followin g ignit on :of saidi charge; I and. ignite means in said firing chargeicham ber and positioned'withi throughsaid propellentjcharge body, saidpa'ssageibeingt unobstructed intermediate said "igniter jrneansland' the; rear end of said bullet'jthereinl whereby said ignitefmeansf I c is efiective t'o ignite"initiallyitheintermediate portion lof f vpr iz l t t' e iflp ssae. Q I: g :1 a perforating j'gnnl wens; having fa bodyf. formed with "anfouter" barrel opening; aninnerf bore of f atof s aidbarrel open?) from thesfinner' e'nd fII said-bar'rlbrienirlg and constittitinga'ifiriiig charge ha 1 ber a barrel threadedintof said Bairflitjtinirrg'afidhzi 1 ing afcoaxial bullet bore therethrough, thejeombination 1; of a bullet -a" tubular-lshaped pro pellen t charge per tioned coaxially "with said firing" charge "chamber, said charge haying a passage? extending-axially therethro'ugh from 'end to "end :thei'eot -and I;havingf' an external diam- .5 eterleSsthan theinternaldiameter of sai firin i i chamberjftraiisve'rlse diaphragm inean's'lo'ca i M ture 'of' saidb rename 11d fiiing clia e-charr ibe bio H agrnrn'ea ns being a v ing with said bullet supported at an ntermedia e 13 relatively short section of said bullet through said central opening and positioned with its rear end exposed to and extending coaxially from said central opening into said firing charge chamber and into said passage in said propellent charge for a substantial portion of the length of said bullet, said bullet making a press fit in said central opening sufficiently tight to delay initial movement of said bullet therefrom into said bullet bore following ignition of said charge; and combustible igniter means in said firing charge chamber and positioned within and located at an intermediate portion of said passage through said propellent charge body, said passage being unobstructed intermediate said igniter means and the rear end of said bullet therein whereby said igniter means is effective to ignite initially the intermediate portion of said propellent charge in said passage.

10. In a perforating gun for wells having a body formed with an outer bullet bore, an inner bore of increased diameter relative to that of said bullet bore and extending coaxially inwardly from the inner end of said bullet bore and constituting a firing charge chamber, the combination of: a bullet; a tubular-shaped propellent charge body positioned coaxially within said firing charge chamber, said charge having a passage extending axially therethrough from end to end thereof and having an external diameter less than the internal diameter of said firing charge chamber; transverse diaphragm means located at the juncture of said bullet bore and firing charge chamber bore, said diaphragm beans being formed with a central opening, with said bullet being supported at an intermediate relatively short section of said bullet through said central opening and positioned with the rear end portion thereof exposed to and extending from said diaphragm means coaxially into said firing charge chamber and into said passage in said propellent charge for a substantial portion of the length of said bullet, said bullet making a press fit in said central opening sufliciently tight to delay initial movement of said bullet therefrom into said bullet bore following ignition of said charge; and combustible igniter means in said firing charge member and positioned within and located at an intermediate portion of said passage through said propellent charge, said passage being unobstructed intermediate said igniter means and the rear end of said bullet therein whereby said ignited means is effective to ignite initially the intermediate portion of said propellent charge in said passage.

11. In a perforating gun for wells having a body formed with an outer bullet bore, an inner bore of increased diameter relative to that of said bullet bore and extending coaxially inward from the inner end of said bullet bore and constituting a firing charge chamber, the combination of: a bullet; a tubular-shaped propellent charge positioned coaxially Within said firing charge chamber, said charge having a passage extending axially therethrough from end to end thereof and having an external diameter less than the internal diameter of said firing charge chamber; a transverse diaphragm located at the juncture of said bullet bore and firing charge chamber bore, said diaphragm being formed with a central opening, with said bullet being supported at an intermediate relatively short section of said bullet through said central opening and positioned with the rear end portion thereof exposed to and extending from said diaphragm coaxially into said firing charge chamber and into said passage in said propellent charge for a substantial portion of the length of said bullet; a restraining annular member encircling and gripping said bullet intermediate the ends of said bullet and positioned adjacent to and on the rearward side of said diaphragm, said bullet making a press fit in said annular member sufficiently tight to delay initial movement of said bore therefrom into said bullet bore following ignition of said charge; and combustible igniter means in said firing charge chamber and positioned within and located at an intermediate portion of said passage through said propellent charge, said passage being unobstructed intermediate said igniter means and the rear end of said bullet therein whereby said igniter means is effective to ignite initially the intermediate portion of said propellent charge in said passage.

12. In a perforating gun for wells having a body formed with an outer bullet bore, an inner bore of increased diameter relative to that of said bullet bore extending coaxially inward from the inner end of said bullet bore and constituting a firing charge chamber, the combination of: a tubular-shaped propellent charge body positioned coaxially within said firing charge chamber, said body having a passage extending axially therethrough from end to end thereof; a transverse diaphragm located at the juncture of said bullet bore and said firing charge chamber bore, said diaphragm being formed with a central opening therethrough; a bullet supported at an intermediate relatively short section thereof through said central opening, with its rear end portion exposed to and extending from said diaphragm opening coaxially into said firing charge chamber for a substantial portion of the length of said bullet; a restraining annular member encircling and gripping said bullet intermediate the ends thereof and positioned on the rearward side of said diaphragm, said bullet making a press fit in said annular member sufiiciently tight to delay initial movement of said bullet therefrom into said bullet bore following ignition of said charge; and igniter means positioned in communication with said passage extending through said propellent charge body, said passage being unobstructed intermediate said igniter means and the said rear end portion of said bullet therein whereby said igniter means is efiective to ignite initially the inner portion of said propellent charge in said passage.

References Cited in the file of this patent UNITED STATES PATENTS 425,574 Lassoe Apr. 15, 1890 677,527 Maxim July 2, 1901 1,166,360 Gregory Dec. 28, 1915 1,835,722 Rembert Dec. 8, 1931 2,029,454 Wells Feb. 4, 1936 2,048,451 Johnston July 21, 1936 2,061,835 Haines Nov. 24, 1936 2,281,870 Cole May 5, 1942 2,328,308 Turechek Aug. 31, 1943 2,358,951 Turechek Sept. 26, 1944 2,419,949 Hottinger May 6, 1947 UNITED STATES PATENT OFFICE L. CERTIFICATE OF CORRECTION Patent No 2,953,971 September 27, 195d Forrest V. Porter It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 7, line l9, for ;"assembly" read assembled column 8, line 29, for "end of read end by column 11, line 42, for "wheels" read wells column 12 line 68, for "with" read within column 13, line 29, for "beans" read means line 45 for "ignited" read igniter Signed and sealed this 25th day of April 196I.

(SEAL) Attel't: ERNEST we. SWIDER DAVID L. LADD Attesting Oficer Commissioner of Patents UNITED STATES PATENT OFFICE i CERTIFICATE OF CORRECTIQN [9w Patent N 2,953,971 September 27, 19

Forrest V. Porter It is hereby certified that error appears in the printed epeeifioetion of the above numbered patent requiring correction and that the said Letters Patent shuuld read as corrected below.

Column 7, line l9, for "assembly" read assembled column 8, line 29 for "end 0f read end by celumn ll line 42, for "wheels" read wells column 12 line 68, for "with" read within column 13, line 29, for "beans," read means line 45 for "ignited" read igniter Signed and sealed this 25th day of April 1961",

( SEAL) Atteet:

ERNEST W1. SWIDER Commissioner of Patents 

